#153 Option for rectangle and/or rounded rectangle) around text

[William Kendrick]

When looking at kids books (e.g., "A Happy Hippo" alphabet book from Scholastic, or any Richard Scarry titles), text on drawings are typically in a white rounded rectangle. Having an option to let kids enable a similar background (either white, or perhaps using the current drawing's background color, if applicable) might be nice. UI-wise, it could be a button over near the Bold/Italic/Size controls, below the font selection.